Bought a 94 Z28 has LT4 intake on it causing me to fail emmissions?
#1
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The girl who owned this car couldnt get it through inspection really high HCs in the 1300s. Has replaced everything related to it even opti. My brother bought the car off her. Doesnt feel like messing with getting it through inspection so i bought it off of him. It has ever single bolt on you can think of, ghost flames, blah blah blah but what stood out is that it has an LT4 intake on it. I was pretty sure these didnt fit so i checked the number and it is infact an origional LT4 intake 12550631 is the number.
I and another LT1 guy am almost positive this is causing a vac leak and why the HC readings are off by so much. Is this intake worth selling? I'm an LS1 guy and have owned a couple LT1s but it was a while ago. I want to sell this intake and buy an LT1 intake. I'm 99% sure the car doesnt have heads or cam done to it. It's an M6 and i dont believe it's ever been tuned. I text her to get a list of the mods, i cant remember them. I know its a full Borla exhaust, mids, cage, 3.73s and all.
Anyway could we be right in thinking this LT4 intake is causing a huge vac leak? Also if i remove the valve covers, whats the head casting number for LT4 heads incase it does have LT4 heads on it too.
I and another LT1 guy am almost positive this is causing a vac leak and why the HC readings are off by so much. Is this intake worth selling? I'm an LS1 guy and have owned a couple LT1s but it was a while ago. I want to sell this intake and buy an LT1 intake. I'm 99% sure the car doesnt have heads or cam done to it. It's an M6 and i dont believe it's ever been tuned. I text her to get a list of the mods, i cant remember them. I know its a full Borla exhaust, mids, cage, 3.73s and all.
Anyway could we be right in thinking this LT4 intake is causing a huge vac leak? Also if i remove the valve covers, whats the head casting number for LT4 heads incase it does have LT4 heads on it too.
#3
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I got a list from the girl who owned it, not sure of any of the spellings she just ran it off to me on the phone.
lt4 intake
moroso cold air intake
edelbrock headers
3" cat with borla exhaust
high flow y pipe
2" lowering springs
strut bar
slp hdzel torsion differential
hotchkis trailing arm and panhardbar
hurst short shifter
3.73 moitive gears
car has ttops, 6 speed, cage is sunset organge/gold with ghost flames, VFN hood and SS spoiler. Got it for $5500.
lt4 intake
moroso cold air intake
edelbrock headers
3" cat with borla exhaust
high flow y pipe
2" lowering springs
strut bar
slp hdzel torsion differential
hotchkis trailing arm and panhardbar
hurst short shifter
3.73 moitive gears
car has ttops, 6 speed, cage is sunset organge/gold with ghost flames, VFN hood and SS spoiler. Got it for $5500.
#5
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The LT4 intake internally is the same as the later LT1 intakes but has more material above the ports that interfere with the valvecover rails if attempts are made to bolt it to LT1 heads. If that material is milled off then it is just a red LT1 intake.
Can you take a picture of how the intake mates to the heads????
Can you take a picture of how the intake mates to the heads????
#6
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with the headers and Y pipe, do you still have a cat on it? and if so, is it the stock cat? i dont know if delaware emissions are as strict as connecticut, but i know of someone who had to take off their headers and y pipe and put back the stock system to pass emissions. also, a few guys at different emissions places mentioned that an aftermarket cat wont pass emissions, only the stock one will. not 100% sure if this is true, but i bought a magnaflow cat and when i heard this, i just said screw it and registered my car in WV where its inspection only. dont know if this helps, just wanted to put it out there.
#7
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It has a 3" or 3.5" high flow cat and shortie headers. I've passed inspection with longtubes before and a high flow cat that shouldnt be it i dont think. I believe the LT4 intake is causing problems. I'll try to get some pictures. Is it possible the car has the LT4 fuel rails and fuel injectors as well? What would the numbers be or how could i tell the difference?
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#10
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I know it's an LT4 intake, and i dont really know what im doing lol. The main question is can an LT4 intake cause a vacuum leak on my car? The car i dont think has ever been tuned for all fo the mods. If the LT4 intake doesnt cause a vac leak then are the LT4 injectors the same as the LT1? I'm thinking maybe the previous owner bought the rail and injectors together then being slightly different and causing the car to run so rich.
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with the mods it has, ide say it could use a tune. especially if different size injectors are used. a lot of people get by with no tune on intake and exhaust bolt ons, but since your havin problems, a mail order tune is what i would try
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I know it's an LT4 intake, and i dont really know what im doing lol. The main question is can an LT4 intake cause a vacuum leak on my car? The car i dont think has ever been tuned for all fo the mods. If the LT4 intake doesnt cause a vac leak then are the LT4 injectors the same as the LT1? I'm thinking maybe the previous owner bought the rail and injectors together then being slightly different and causing the car to run so rich.
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#14
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A 3264 17095004 is what i found on the top of the injector. LT by the connector. Also i noticed that there were 4 'tabs' maybe is the word that look like that have been ground down. Like they are at say 4 corners of the intake where it makes to the valve covers it looks like they have been ground down to miss the valve covers. Im not sure i only assume because they are not painted on the side like the rest of the intake.
#15
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All those mods without a tune? Possible larger injectors, with no tune. That's your problem.
If you're so sure you have a vac leak, get a vac gauge. They are cheap to buy. Easy test, should be around 15lbs of vaccum. (not 100% on that number with this engine)
If you're so sure you have a vac leak, get a vac gauge. They are cheap to buy. Easy test, should be around 15lbs of vaccum. (not 100% on that number with this engine)
#16
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Ran the numbers thos are stock 94 LT1 injectors so thats not the problem. I noticed that one did spin pretty easy when i was looking for numbers maybe ill put a little silicone caulk around the that injector seat. No tune that i know of. I remember on mine i had a mail order tune sent to my email account and i had my friend upload it. Who does those tunes now? I forgot who did mine it was so long ago.
#18
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http://a296.ac-images.myspacecdn.com...ddff081687.jpg
Cage is painted to match the car, lowered, gfx kit, engine bay is painted same color, etc.etc. it was a show car with alot of bolt onts. It's done up really nice, not a cheap or half assed paint job. The ghost flames look awesome in the sunlight. Its just going to be my DD my fast car is the ls1 68 bird whose cage im welding directly to the subframe.
Cage is painted to match the car, lowered, gfx kit, engine bay is painted same color, etc.etc. it was a show car with alot of bolt onts. It's done up really nice, not a cheap or half assed paint job. The ghost flames look awesome in the sunlight. Its just going to be my DD my fast car is the ls1 68 bird whose cage im welding directly to the subframe.
#19
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I tried the shoe box method of pushing on the diaphram of the EGR and i cant get it to move. I can feel it move slightly towards the outside with it off and with it on just a tiny bit but it really doesnt move and the engine doesnt change sound at all when i do it. I've got pretty strong fingers so either im pressing the wrong thing or my egr valve is bad.
#20
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I doesn’t sound to me that you have a vacuum leak. The motor would run pretty bad and hunt for a stable idle speed or have a very high idle speed. As I recall, high hydrocarbons are caused by too low a combustion chamber temperature. The job of the EGR valve is to raise this temperature. Get that EGR system working well and try another inspection. If you want to make sure it’s good and hot when you go, unplug the left (driver’s side) fan. It comes on first, the other at a higher temperature. While you’re at it, are your plugs good? Poor ignition will hurt you. Also, make sure there aren’t any lurking codes that aren’t triggering the SES light.
Good luck!
Good luck!